> Hi,
>
>
> suppose I use the following code for fact
>
> let rec fact n = if n <= 1 then 1 else n * fact (n - 1) ;;
>
> Because an integer number is represented by a fixed number of bytes I will
> get a runtime overflow if n is chosen too large.
>
> Is there in Ocamel a workaround to cope with this problem . Something like "
> Onoverflow goto .. " in imperative languages.
>
> Thx
>
> Scott
>
>
There is no such feature as a Onoverflow goto, because
Ocaml (and not OCamel...) default integers are not << real >> integers,
but machine integers on some size (typically 31 or 63) bits.
This means that maxint + 1 is minint and basically this is the
behavior of C.
I guess the reason why is avoiding putting non-obvious tests
everywhere.
Most of the time you do not need those tests.
* If you want ``real'' integers, you can use some arbitrary
precision library (Num, etc.), overflow detection would not help
here anyway.
* If you want to be warned on overflow, you have to devise the tests
by yourself, and then you can use an exception as your
Onoverflow goto
An easy one :
expection Overflow
let protected_incr x =
let y = x+1 in
if y > x then y
else raise Overflow
try
.... incr (..)
with
| Overflow -> ... do whatever you can ...
Hope it helps.
--Luc
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